KR101135598B1 - Compositions of grinding aids for the improving of grinding cement clinkers - Google Patents

Abstract

PURPOSE: A grinding aid composition for cement clinker fine-grinding is provided to shorten grinding time of the cement clinker and improve milling characteristic and hydration property. CONSTITUTION: A grinding aid composition for cement clinker fine-grinding comprises polycarbonic acid substituted with inorganic salt and amine having a glycerin group. The glycerin group is selected from a group including glycerin dimethylamine, glycerin ethylamine, diglycerin methylamine, diglycerin ethylamine, diglycerin monoethanolamine, mono glycerin diglycerin diethanolamine, and triglycerin amine. The inorganic salt is more than one type which is selected from a group including sodium salt, potassium salt, calcium salt, magnesium salt, lithium salt and Aluminium salt. The polycarbonic acid is selected from a group including polyacrylate, methacrylic acid polymer, acrylic acid methacrylic acid copolymer, and maleic anhydride acrylic acid copolymer.

Description

Grinding aid composition for fine grinding of cement clinker {COMPOSITIONS OF GRINDING AIDS FOR THE IMPROVING OF GRINDING CEMENT CLINKERS}

The present invention relates to a grinding aid composition for pulverizing cement clinker, and more particularly to a grinding aid composition for pulverizing cement clinker comprising polycarboxylic acid substituted with an amine or inorganic salt having a glycerin group. will be.

In general, raw materials used in cement production in the cement industry include limestone, silica, clay, iron ore, slag or mixtures thereof, and coke, sludge, dust, etc. After the treatment at about 1,450 ° C. in a kiln, the limestone component in the raw material is combined with silica, alumina and iron to form cement minerals. This mineral hardens when reacted with water. This mineral is called a cement clinker, which is cooled and then powdered together with a small amount of gypsum (calcium sulfate) in a finishing mill to provide a homogeneous powdery product called portland cement.

In the cement manufacturing process as described above, the grinding is the final step of quality control, and the grinding is a key process together with the firing process because the performance of the final product is determined by the grinding process. The purpose of the grinding is to increase the reactivity of the cement powder by making the cement clinker into fine particles to increase the surface area, and to grind the minerals (limestone, blast furnace slag, etc.) used as a mixed material to take useful ingredients and increase the mixing effect.

The clinker requires a large amount of energy for micronization because of its extremely high hardness. Depending on the nature of the clinker, the energy required for finishing grinding is known to be about 33 to 77 kWh / ton. Therefore, research has been conducted to improve the grinding efficiency by adding an additive when grinding cement clinker. At this time, the grinding aid used to maximize the efficiency of the grinding (Grinding Aid). To date, it has been found that the addition of several substances, such as glycols, alkanolamines, aromatic acetic acid, etc. to the clinker at a predetermined rate reduces the amount of energy required and improves the grinding efficiency of the hard clinker.

On the other hand, the grinding aid as described above affects the flow characteristics of the powder and the mill residence time of the pulverized product in addition to preventing the agglomeration of the powder and coating inside the mill. It improves powder fluidity by removing surface energy that causes coagulation and intergranular attraction caused by coagulation, and smoothly discharges already ground fine powder together with ventilated air out of the mill. In addition, by reducing the amount of fine particles recycled into the mill is known to play a role in improving the productivity when grinding cement clinker.

Korean Patent Registration No. 222776 discloses a method for performing fine grinding of cement clinker using waste antifreeze containing glycol as a main component. In addition, Korean Patent No. 441010 discloses a grinding aid preparation method using diethylene glycol or triethanolamine. In the registered publication of Patent No. 150209, a grinding aid using triisopropanolamine and a cement composition including the grinding aid are disclosed. In addition, US Pat. Nos. 4,482,424 and 4,048,77 disclose examples of using a grinding aid for the purpose of delaying the hydration of cement and mixing the mixing ratio for the two-component system used as the grinding aid.

Recently, in order to improve the hydration characteristics of cement or to improve the compressive strength, in addition to the effects of conventional concepts such as the increase in mill efficiency due to the development of powder engineering and the demand for quality improvement, Grinding aid research continues.

The problem to be solved in the present invention is to use a separate compound or mixture different from the existing product to improve the optimizing quality and the hydration characteristics and increase the long-term compressive strength by increasing the efficiency of the grinding process It is to provide.

In order to solve the above problems, the present invention provides a grinding aid composition for pulverizing cement clinker comprising a polycarboxylic acid substituted with an amine or an inorganic salt having a glycerin group.

The amine having the glycerin group is glycerin dimethylamine, glycerin ethylamine, diglycerin methylamine, diglycerin ethylamine. It is preferable that it is selected from the group which consists of a diglycerol monoethanolamine, a monoglycerine diethanolamine, and a triglycerinamine.

It is preferable that the said inorganic salt is selected from the group which consists of a sodium salt, potassium salt, calcium salt, magnesium salt, lithium salt, and aluminum salt.

It is preferable that the said polycarboxylic acid is chosen from the group which consists of an acrylic acid polymer, a methacrylic acid polymer, an acrylic acid methacrylate copolymer, and an acrylic acid maleic anhydride copolymer.

The polycarboxylic acid preferably has an average molecular weight (Mw) of 1,000 to 20,000.

As described above, the grinding aid composition for pulverizing the cement clinker of the present invention is added during the grinding of the cement clinker to shorten the grinding time, remarkable energy saving effect, improve the grinding characteristics and hydration characteristics, the grinding aid composition is The added cement has increased compressive strengths of 1 day, 3 days, 7 days and 28 days.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

As described above, conventional grinding aids include compounds such as glycols or triisopropanolamine. However, the compound had a somewhat insufficient effect of improving the grinding efficiency and compressive strength. Korean Patent No. 150209 described above describes that triethanolamine and the like increase the compressive strength at an early age of cement. However, these compounds are generally limited in their use at 28 days of age, or because they reduce the compressive strength in concrete due to the increase in the amount of bubbles and air in concrete. Therefore, the present inventors, while showing a superior grinding efficiency than the conventional grinding aid, after studying the new grinding aid composition that can enhance the compressive strength when added to the cement, the cement clinker grinding mill composition of the present invention Was developed.

Accordingly, the present invention provides a grinding aid composition for pulverizing cement clinker comprising a polycarboxylic acid substituted with an amine or an inorganic salt having a glycerin group.

The amine having the glycerin group is glycerin dimethylamine, glycerin ethylamine, diglycerin methylamine, diglycerin ethylamine. It is preferable that it is selected from the group which consists of a diglycerol monoethanolamine, a monoglycerine diethanolamine, and a triglycerinamine.

The amine having the glycerin group can be produced, for example, by the following production method. Specifically, glycidol represented by [Formula 1] below or glycerin represented by [Formula 2] below in ammonia, monomethylamine, dimethylamine, monoethylamine, diethylamine, monoethanolamine, and diethanolamine It can be prepared by adding 1 to 4 moles of carbonate.

It is preferable that the said inorganic salt is selected from the group which consists of a sodium salt, potassium salt, calcium salt, magnesium salt, lithium salt, and aluminum salt.

Therefore, at least one of the inorganic salts may be substituted with the carboxyl group of the polycarboxylic acid.

It is preferable that the said polycarboxylic acid is chosen from the group which consists of an acrylic acid polymer, a methacrylic acid polymer, an acrylic acid methacrylate copolymer, and an acrylic acid maleic anhydride copolymer.

The polycarboxylic acid has an average molecular weight (Mw) of 1,000 to 20,000, preferably 2,000 to 8,000.

In addition, the carboxyl group of the polycarboxylic acid of the present invention may be substituted with an amine instead of being substituted with an inorganic salt.

Substitutable amines include one or more from the group consisting of ammonia, trimethylamine, dimethylamine, monomethylamine, monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, monoethanoldiisopropanolamine and diethanol monoisopropanolamine Is selected.

In addition, the grinding aid composition of the present invention may use a mixture of 10 to 90% by weight of an amine having a glycerin group and 10 to 90% by weight of a polycarboxylic acid substituted with an inorganic salt or an amine.

In addition, the grinding aid composition of the present invention may further include alkylene glycol and / or alkanolamine in addition to the amine having a glycerin group described above, an inorganic salt or a polycarboxylic acid substituted with an amine, or a mixture thereof. .

Examples of the alkylene glycol include monoethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol and the like.

Examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, monoisopropanol diethanolamine, diisopropanol monoethanolamine, triisopropanolamine, ethylene-1,1,4,4-tetraethanolamine, and the like. Can be.

As described above, the grinding aid composition for pulverizing the cement clinker of the present invention is preferably added in a range of 0.005 to 0.2% by weight based on the total weight of the cement clinker, more preferably 0.01 to 0.05 based on the total weight of the cement clinker. It is preferred to add in the range by weight. When the cement clinker fine grinding aid composition is added in less than 0.005% by weight based on the total weight of the cement clinker, it may not sufficiently exhibit the effect of pulverization, whereas when it exceeds 0.2% by weight, the effect of pulverization is improved. This is because it is not large and it is uneconomical.

Known cement additives, such as air entrainers, may be added to alter the final physical properties of the cement when using the grinding aid composition as described above.

When the cement clinker grinding mill composition of the present invention prepared in the above-described ratio is added in a range of 0.005 to 0.2% by weight relative to the total weight of the cement clinker to be made of cement, the grinding aid composition for grinding cement clinker is It is adsorbed on the surface of the finely divided particles to reduce the aggregation phenomenon between the particles. Therefore, the pulverized particles can be smoothly discharged out of the mill together with the ventilation air as well as the coating phenomenon on the wall surface of the mill due to the flocculation of the pulverized particles is removed, and the crushing effect by the fine powder is reduced to improve the grinding efficiency. . In addition, the primary pulverized particles in the mill increase the particle and dispersibility even in the air classifier that separates the fine and coarse powder (as a result of improving the classification efficiency of the classifier), thereby reducing the amount of fine powder recycled to the mill. By increasing the productivity of the cement clinker grinding.

The grinding aid composition of the present invention may be added before, during or after grinding of the cement clinker. As the name of the present invention, the grinding aid composition of the present invention is preferably added during the grinding of the cement clinker, that is, before or during grinding, but after the grinding of the cement clinker in view of increasing the compressive strength, that is, after the cement is manufactured. May be

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments of the present invention. However, the following examples are only for the purpose of understanding the present invention and the scope of the present invention is not limited only to the following examples.

[ Example ]

Into a 500 ml four-necked flask equipped with a cooler, a stirrer, a nitrogen introduction tube, and a dropping cylinder, 1.5 mol (210.3 g) of diethanolamine was added and stirred while heating to 70 ° C. The reaction temperature was maintained at 70 ° C. and 1.5 mol (111 g) of glycidol was added dropwise for 6 hours using a dropping cylinder. After reacting until the oxirane concentration was less than 0.1%, 320 g of a glycerin diethanolamine as a reactant was obtained (Scheme 1).

Scheme 1

2 mol (122 g) of monoethanolamine was put into 500 ml of the same four neck flasks as Example 1, and it stirred, heating at 70 degreeC. The reaction temperature was maintained at 70 ° C, and 4 mol (296 g) of glycidol was added dropwise for 8 hours using a dropping cylinder. After reacting until the oxirane concentration became less than 0.1%, 410 g of diglycerin monoethanolamine as a reactant was obtained.

500 g of polyacrylic acid having a molecular weight of 4,500, which is a 40% aqueous solution, was added to a 1,000 ml three-necked flask equipped with a stirrer, and stirred at 50 ° C., neutralized by dropping 50 g of NaOH 100 gdmf for 30 minutes, followed by adding 20 g of Li ₂ CO ₃ thereto for 30 minutes. By stirring, a polyacrylate (Formula 3) in which the polyacrylic acid was partially neutralized with Na and Li was prepared.

Test Example

In order to confirm the effect on the cement clinker grinding of the prepared examples 1 to 3 material 2900 g of clinker, 100 g of anhydrous gypsum in a ball mill (Ball Mill) and without the grinding aid and conventional grinding The case of adding 0.6 g of diethylene glycol (DEG), which is frequently used as a preparation, and adding 0.6 g of the grinding aid of Examples 1 to 3, respectively, were operated for 30 minutes and operated with a mille value. A small amount of sample was collected, and again subjected to grinding to perform a blain value measurement test and a sifting test on the ground cement sample for a total of 60 minutes, and the results are shown in Table 1.

Grinding aid sample
Blaine value (cm ² / g)
Residual rate (40 μm) 30 minutes grinding 60 minutes grinding       No additives 2,102 3,012 14.5% DEG 2,270 3,184 12.6% Example 1 2,291 3,238 11.9% Example 2 2,295 3,235 11.5% Example 3 2,288 2,246 11.8%

In addition, a physical test was performed to confirm the result of the hydration reaction of cement, and the results are shown in Table 2 below.

Grinding Preparation Sample
Stability Vicarcup Condensation Time
Flow
(mm) Compressive strength (MPa) First
(minute) closing
(hour minute)
1 day
3 days
7 days
28 days No additives 0.65% 54 4:00 172 10.2 17.5 22.1 33.5 DEG 0.58% 51 3:55 175 11.2 18.2 23.6 35.1 Example 1 0.60% 48 3:50 171 12.1 19.5 25.5 38.3 Example 2 0.57% 50 3:45 172 12.5 20.0 25.0 38.0 Example 3 0.58% 48 3:50 175 12.0 19.6 26.0 38.8

As can be seen from the above test results, Examples 1 to 3 of the present invention is excellent in the rain value, the residual ratio, the compressive strength compared to the case without addition of the grinding aid and DEG added Can be.

For reference, the test was carried out according to the Portland cement test method of the KS standard of the following Table 3.

Test Items KS standard Fineness measurement KS L 5106 Autoclave Expansion KS L 5107 Vicat Needle Condensation Time KS L ISO 9597 Compressive strength KS L ISO 679

Claims (5)

An amine having a glycerin group,
The amine having the glycerin group is glycerin dimethylamine, glycerin ethylamine, diglycerin methylamine, diglycerin ethylamine. Diglycerin monoethanolamine, monoglycerin diethanolamine, and triglycerine amine selected from the group which consists of the grinding aid composition for fine grinding of cement clinker characterized by the above-mentioned. delete delete delete delete